Chaperone action of a versatile small heat shock protein from Methanococcoides burtonii, a cold adapted archaeon.
The Methanococcoides burtonii small heat shock protein (Mb-sHsp) is an alphaB-crystallin homolog that delivers protein stabilizing and protective functions to model enzymes, presumably reflecting its role as a molecular chaperone in vivo. Although the gene encoding Mb-shsp was cloned from a cold-adapted microorganism, the Mb-sHsp is an efficient protein chaperone at temperatures far above the optimum growth temperature of M. burtonii. We show that Mb-sHsp can prevent aggregation in E. coli cell free extracts at 60 degrees C for 4 h and can stabilize bovine liver glutamate dehydrogenase for 3 h at 50 degrees C. Surface plasmon resonance was used to determine the binding affinity of Mb-sHsp for denatured proteins. Mb-sHsp bound tightly to denatured lysozyme but not to the native form. When Mb-Cpn and Mg(2+)-ATP were added to the reaction, bound lysozyme was released from Mb-sHsp establishing that Mb-Cpn is able to off-load folding intermediates from Mb-sHsp. In addition, Mb-sHsp and Mb-Cpn also function cooperatively to protect an enzyme substrate. Through characterization of these M. burtonii chaperones, we were able to reconstitute a key heat shock regulated protein folding function of this cold adapted organism in vitro.
Laksanalamai
Pongpan
P
Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, Maryland 21202, USA. pongpan@comb.umbi.umd.edu
Narayan
Suchithra
S
Luo
Haibin
H
Robb
Frank T
FT
D000595:Amino Acid Sequence; D000818:Animals; D019843:Archaeal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002417:Cattle; D018833:Chaperonins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D003001:Cloning, Molecular; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D050888:Heat-Shock Proteins, Small / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006358:Hot Temperature; D017019:Methanosarcinaceae / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009113:Muramidase / Q000378:metabolism; D011485:Protein Binding; D011489:Protein Denaturation
D019843:Archaeal Proteins; D050888:Heat-Shock Proteins, Small; D005969:Glutamate Dehydrogenase; D009113:Muramidase; D018833:Chaperonins